1. Technical Field
The present invention relates to a biological sample reaction chip and a biological sample reaction method for performing biological sample reactions such as nucleic acid amplification.
2. Related Art
One method that has come to the forefront involves using a microfluid chip, in which a fine channel is provided to a glass plate or the like, to perform chemical analysis, chemical synthesis, bio-related analysis, and the like. These microfluid chips are also called micro total analytical systems (micro TAS), lab-on-a-chip, and so on, the advantages to which are that less sample or reagent is required than with conventional devices, the reaction time is shorter, there is less waste, and so forth, and these chips are expected to find use in a wide range of fields, such as medical diagnosis, on-site analysis of environments and foods, and the production of drugs, chemicals, and the like. Since a smaller amount of reagent may be used, the cost of testing can be reduced, and because the amount of sample and reagent is smaller, the reaction time is also much shorter, so the testing is more efficient. Particularly when these chips are used for medical diagnosis, since less blood or other specimen that serves as the sample is required, another advantage is that it reduces the burden on the patient.
The polymerase chain reaction (PCR) method is well known as a way to amplify the genes of DNA, RNA, and the like used as reagents and samples. PCR involves putting a mixture of the target DNA and a reagent into a tube, and repeatedly reacting the mixture with a temperature control apparatus called a thermal cycler, with temperature changes in three stages of 55° C., 72° C., and 94° C. repeated at a cycle of a few minutes. The action of the enzyme polymerase allows the target DNA to be amplified by approximately 2 times per temperature cycle.
A method called real time PCR, in which a special fluorescent probe is used, has become practical in recent years, and allows DNA to be quantified while performing an amplification reaction. Since real time PCR affords high measurement accuracy and reliability, it has come to be widely used for research and clinical testing purposes.
With a conventional device, however, the amount of reaction solution needed for PCR is typically a few dozen microliters, and a problem is that basically only one gene can be measured with a single reaction system. With another method, about four different genes can be measured simultaneously by using a plurality of fluorescent probes and differentiating by color, but the only way to simultaneously measure more genes than this is to increase the number of reaction systems. The amount of DNA extracted from a specimen is generally very small, and reagents are expensive, so measuring many reaction systems at the same time is problematic.
JP-A-2000-236876 discloses a method in which integrated microwells are produced on a semiconductor substrate, and PCR is conducted in these wells, allowing many different DNA samples to be amplified and analyzed at the same time using only tiny amounts of sample.
However, JP-A-2000-236876 does not disclose a specific method for introducing a tiny amount of sample into a well. Actually, it was very difficult in the past to quantify a tiny amount (1 μL or less) of reaction solution and efficiently supply it to a reaction vessel.